1. Field of the Invention
The present invention relates generally to a cable connecting apparatus, and more particularly to an improvement in a cable connecting apparatus which comprises a plug type connector with which a plurality of cables such as coaxial cables are coupled and a receptacle type connector which is provided with an opening through which a connectively engaging portion of the plug type connector is inserted in the receptacle type connector, and is used for connecting electrically the cables coupled with the plug type connector with an electrical device such as an electric circuit board to which the receptacle type connector is fixed to be electrically connected therewith.
2. Description of the Prior Art
When a plurality of cables such as coaxial cables for transmitting various kinds of electric signals, voltages and so on, each of which is relatively slender, are electrically connected to an electric circuit board, on which various electrical parts are mounted, in a such manner as to be bundled to form a thin flat cable assembly, there has been proposed to use often a cable connecting apparatus which is operative to mediate between the cables and the electric circuit board with which the cables are to be electrically connected. The cable connecting apparatus thus used comprises, for example, a plug type connector having a connectively engaging portion with which the cables are coupled and a receptacle type connector provided with an opening through which the connectively engaging portion of the plug type connector is inserted in the receptacle type connector.
In the cable connecting apparatus used for connecting electrically the cables to the electric circuit board in such a manner as mentioned above, a plurality of plug contacts, with which the cables are connected respectively, are provided to be arranged on the connectively engaging portion of the plug type connector and a plurality of receptacle contacts, a portion of each of which is connected with a circuit portion provided on the electric circuit board, are provided to be arranged at the inside of the opening of the receptacle type connector. When the connectively engaging portion of the plug type connector is inserted through the opening in the receptacle type connector, the receptacle contacts come into press-contact respectively with the plug contacts to be electrically connected with the same so that the cables are electrically connected through the plug type and receptacle type connectors with the circuit portion on the electric circuit board.
In regard to the cable connecting apparatus wherein the connectively engaging portion of the plug type connector is inserted in the receptacle type connector through the opening provided thereon as mentioned above, it has been desired to be miniaturized in thickness as a whole so as to connect the cables each of which is still more slenderized with the electric circuit board which is still more miniaturized in size and reduced in weight. Accordingly, it has been required for the plug type connector to have an improved connectively engaging portion reduced in thickness as much as possible and it has been also required for the receptacle type connector to have a plurality of improved receptacle contacts which are able to come surely into press-contact respectively with the plug contacts provided on the connectively engaging portion of the plug type connector reduced in thickness and to keep the press-contact with the plug contacts stable.
Under such a situation, there has been previously proposed a cable connecting apparatus comprising a plug type connector and a receptacle type connector to be used for connecting electrically a plurality of cables with an electric circuit board, wherein each of plug contacts provided on a connectively engaging portion of the plug type connector to be connected with the cable is formed to have a pair of contacting surfaces opposite to each other and each of receptacle contacts provided on the receptacle type connector is formed to have a pair of contacting portions operative to come into press-contact respectively with the contacting surfaces of the plug contact so as to cause the receptacle contact to be connected electrically with the plug contact, as disclosed in, for example, the Japanese patent application published before examination under publication number 2007-73426 (hereinafter, referred to as published patent document 1). Further, there has been also previously proposed another cable connecting apparatus comprising a plug type connector and a receptacle type connector to be used for connecting electrically a plurality of cables with an electric circuit board, wherein each of plug contacts provided on a connectively engaging portion of the plug type connector is formed to have a plate member extending along a core wire of the cable which is connected with the plug contact and having a pair of opposite surfaces, on one of which the core wire of the cable is placed, and each of receptacle contacts provided on the receptacle type connector is formed to have a contacting point operative to come into contact with the other of the opposite surfaces of the plate member of the plug contact so as to cause the receptacle contact to be connected electrically with the plug contact, as disclosed in, for example, the Japanese patent application published before examination under publication number 2005-158677 (hereinafter, referred to as published patent document 2).
In the previously proposed cable connecting apparatus disclosed in the published patent document 1, each of a plurality of plug contacts (male terminals 50) provided to be arranged on a connectively engaging portion of a plug type connector (a plug 2) is constituted to be a three-layer structure in which a conductive plate member is folded to form a pair of plate portions (the upper and lower plate portion 52 and 53) facing each other with a plastic plate member which is a part of a housing (20) between or an incorporated structure formed by causing a relatively thick conductive plate member to be subjected to processing for punching so as to have a pair of contacting surfaces (an outer surface of an upper plate portion 52 and an outer surface of a lower plate portion 53) opposite to each other. Further, each of a plurality of receptacle contacts (female terminals 80) provided to be arranged on a receptacle type connector (a receptacle 6) is provided with a fork-shaped portion having a pair of contacting projections (contacting points 81 and 82) facing each other with the contacting surfaces of the plug contact constituted to be the three-layer structure or the incorporated structure between.
The contacting projections of each of the receptacle contacts are operative to come into contact respectively with the contacting surfaces of one of the plug contacts from the outside thereof so that the plug contacts are electrically connected respectively with the receptacle contacts.
In another previously proposed cable connecting apparatus disclosed in the published patent document 2, each of a plurality of plug contacts (terminals 12) provided to be arranged on a connectively engaging portion forming a part of a housing (11) of a plug type connector (a cable connector 1) is provided with a plate member extending along a core wire (22a) of a cable (22) set to be soldered to the plate member so as to form a contacting portion (20) and an end portion of the plate member is folded back to form a projecting end portion (folded portion 18). Further, each of a plurality of receptacle contacts (terminals 33) provided to be arranged on a receptacle type connector (a mate connector 31) is provided with a contacting point (36) operative to come into contact with a surface of the plate member of the plug contact, which is opposite to another surface of the plate member to which the core wire of the cable is soldered.
With the contacting point of each of the receptacle contact put in contact with the surface of the plate member of each of the plug contact, the receptacle contact is electrically connected with the plug contact.
In the cable connecting apparatus proposed previously as disclosed in the published patent document 1, which comprises the plug type connector and the receptacle type connector to be used for connecting electrically the cables with the electric circuit board and in which each of the plug contacts provided on the connectively engaging portion of the plug type connector is constituted to be the three-layer structure or the incorporated structure to form the contacting surfaces opposite to each other and each of the receptacle contacts provided on the receptacle type connector is provided with the fork-shaped portion having the contacting projections facing each other with the contacting surfaces of the plug contact constituted to be the three-layer structure or the incorporated structure between, the receptacle contact is operative to cause the contacting projections thereof to come into contact respectively with the contacting surfaces of the same portion of the plug contact in two directions opposite to each other when the contacting projections of each of the receptacle contacts comes into contact respectively with the contacting surfaces of one of the plug contacts from the outside thereof.
Therefore, in each of the plug contacts, pressure by the contacting projections of the receptacle contact concentrates to a particular portion of the plug contact and such particular portions of the plug contacts are arranged in a line extending in a direction along which the plug contacts are arranged. As a result, it is feared that, under a condition where the connecting projections of each of the receptacle contacts are put in press-contact with one of the plug contacts, the connectively engaging portion of the plug type connector becomes unstable in its posture and brings about undesirable changes in its posture and position.
Besides, in the case where each of the plug contacts is constituted to be the three-layer structure, it is difficult to reduce enough the thickness of each of the plug contacts and therefore also difficult to reduce effectively the thickness of the connectively engaging portion of the plug type connector, and in the case where each of the plug contacts is constituted to be the incorporated structure, it is required to cause the relatively thick conductive plate member to be subjected to processing for punching, which is improved to be extremely highly precise, and in addition it is feared that the plug contacts are not surely stuck on insulating material such as plastics forming the connectively engaging portion of the plug type connector.
Further, in the cable connecting apparatus proposed previously as disclosed in the publication patent document 2, which comprises the plug type connector and the receptacle type connector to be used for connecting electrically the cables to the electric circuit board and in which each of the plug contacts is provided with the plate member to which the core wire of the cable are soldered for forming the contacting portion and the end portion of the plate member is folded back to form the projecting end portion and each of the receptacle contacts is provided with the contacting point operative to come into contact with the surface of the plate member of the plug contact, which is opposite to another surface of the plate member to which the core wire of the cable is soldered, since the plug contacts are pressed into the housing of the plug type connector and stuck on insulating material such as plastics forming the housing at a relatively small area, it is also feared that the plug contacts are not surely stuck on the insulating material forming the connectively engaging portion as the part of the housing of the plug type connector.